4 files changed, 23 insertions, 7 deletions
diff --git a/Lib/locale.py b/Lib/locale.py
index 3dc4caf..58cf0a7 100644
--- a/Lib/locale.py
+++ b/Lib/locale.py
@@ -440,13 +440,17 @@ def _build_localename(localetuple):
         No aliasing or normalizing takes place.
 
     """
-    language, encoding = localetuple
-    if language is None:
-        language = 'C'
-    if encoding is None:
-        return language
-    else:
-        return language + '.' + encoding
+    try:
+        language, encoding = localetuple
+
+        if language is None:
+            language = 'C'
+        if encoding is None:
+            return language
+        else:
+            return language + '.' + encoding
+    except (TypeError, ValueError):
+        raise TypeError('Locale must be None, a string, or an iterable of two strings -- language code, encoding.')
 
 def getdefaultlocale(envvars=('LC_ALL', 'LC_CTYPE', 'LANG', 'LANGUAGE')):
 
diff --git a/Lib/test/test_locale.py b/Lib/test/test_locale.py
index 5d4b5fb..30480c1 100644
--- a/Lib/test/test_locale.py
+++ b/Lib/test/test_locale.py
@@ -407,6 +407,14 @@ class TestMiscellaneous(unittest.TestCase):
         locale.setlocale(locale.LC_CTYPE, loc)
         self.assertEqual(loc, locale.getlocale(locale.LC_CTYPE))
 
+    def test_invalid_locale_format_in_localetuple(self):
+        with self.assertRaises(TypeError):
+            locale.setlocale(locale.LC_ALL, b'fi_FI')
+
+    def test_invalid_iterable_in_localetuple(self):
+        with self.assertRaises(TypeError):
+            locale.setlocale(locale.LC_ALL, (b'not', b'valid'))
+
 
 def test_main():
     tests = [
diff --git a/Misc/ACKS b/Misc/ACKS
index 5536ac6..6f2c2a1 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -717,6 +717,7 @@ John Popplewell
 Amrit Prem
 Paul Prescod
 Donovan Preston
+Jyrki Pulliainen
 Steve Purcell
 Fernando Pérez
 Eduardo Pérez
diff --git a/Misc/NEWS b/Misc/NEWS
index c91c094..7ef1977 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -66,6 +66,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #3067: locale.setlocale() now raises TypeError if the second
+  argument is an invalid iterable. Initial patch by Jyrki Pulliainen.
+
 - Issue #13140: Fix the daemon_threads attribute of ThreadingMixIn.
 
 - Issue #13339: Fix compile error in posixmodule.c due to missing semicolon.